Lead with braided reinforcement

ABSTRACT

A therapy delivery element configured for at least partial insertion in a living body. A braided structure surrounds the conductor assembly. A distal end of the braided structure is attached to an electrode assembly and a free floating proximal end is located near a connector assembly. An outer tubing surrounds the braided structure. The outer tubing includes a proximal end attached to the connector assembly and a distal end attached to the braided structure near the electrode assembly. A proximal tension force applied to the connector assembly acts substantially on the outer tubing and the conductor assembly and a proximal tension force applied to the free floating proximal end acts substantially on the braided structure.

CLAIM OF PRIORITY

This application is a divisional of and claims the benefit of priorityunder 35 U.S.C. §120 to Finley et al., U.S. patent application Ser. No.13/572,081, entitled “LEAD WITH BRAIDED REINFORCEMENT”, filed on Aug.10, 2012, which is incorporated by reference herein in its entirety.

FIELD

The present disclosure is directed to a method and apparatus that allowsfor stimulation of body tissue, particularly nerves. More specifically,this disclosure relates to an implantable medical electrical lead with abraided reinforcement. The present lead can be used with or withoutfixation structures to provide stability for the stimulation electrodes.Moreover, this disclosure relates to the method of implantation andanchoring of the medical electrical lead electrodes in operativerelation to a selected nerve to allow for stimulation.

BACKGROUND

Implantable medical electronics devices consist of an implanted pulsegenerator that is used to provide electrical stimulation to certaintissues and an implantable lead or leads that are used to transmit theelectrical impulse to the targeted tissues. Examples include cardiacpacemaking, and a number of related applications for cardiac rhythmmanagement, treatments for congestive heart failure, and implanteddefibrillators. Other applications for implantable pulse generatorsinclude neurostimulation with a wide range of uses such as pain control,nervous tremor mitigation, incontinent treatment, epilepsy seizurereduction, vagus nerve stimulation, for clinical depression, and thelike.

Despite various suture fixation devices, nerve stimulation leads can bedislodged from the most efficacious location due to stresses placed onthe lead by the ambulatory patient. A surgical intervention is thennecessary to reposition the electrode and affix the lead. Theimplantable pulse generator (“IPG”) is programmed to deliver stimulationpulse energy to the electrode providing the optimal nerve response. Theefficacy of the selected electrode can fade over time due todislodgement or other causes.

Physicians spend a great deal of time with the patient under a generalanesthetic placing the small size stimulation electrodes relative to thetarget nerves. The patient is thereby exposed to the additional dangersassociated with extended periods of time under a general anesthetic.Movement of the lead, whether over time from suture release or duringimplantation during suture sleeve installation, is to be avoided. As canbe appreciated, unintended movement of any object positioned proximate anerve may cause unintended nerve damage. Moreover reliable stimulationof a nerve requires consistent nerve response to the electricalstimulation that, in turn, requires consistent presence of thestimulation electrode proximate the target nerve. On the other hand, ifthe target nerve is too close to the electrode, inflammation or injuryto the nerve can result, diminishing efficacy and possibly causingpatient discomfort.

Cardiac pacing leads are commonly provided with passive fixationmechanisms that non-invasively engage heart tissue in a heart chamber orcardiac blood vessel or active fixation mechanisms that invasivelyextend into the myocardium from the endocardium or epicardium.Endocardial pacing leads having pliant tines that provide passivefixation within interstices of trabeculae in the right ventricle andatrial appendage are well known in the art as exemplified by U.S. Pat.Nos. 3,902,501, 3,939,843, 4,033,357, 4,236,529, 4,269,198, 4,301,815,4,402,328, 4,409,994, and 4,883,070, for example. Such tined leadstypically employ tines that extend outwardly and proximally from a bandproximal to a distal tip pace/sense electrode and that catch in naturaltrabecular interstices when the distal tip electrode is advanced intothe a trial appendage or the ventricular apex.

Certain spinal cord stimulation leads have been proposed employing tinesand/or vanes as stand-offs to urge the stimulation electrode in theepidural space toward the spinal cord as disclosed in U.S. Pat. Nos.4,590,949 and 4,658,535, for example, and to stabilize the stimulationelectrode in the epidural space as disclosed in U.S. Pat. No. 4,414,986,for example.

Stimulation leads for certain pelvic floor disorders have been proposedwith a fixation mechanism that includes a plurality of tine elementsarrayed in a tine element array along a segment of the lead proximal tothe stimulation electrode array, such as for example in U.S. Pat. Nos.6,999,819; 7,330,764; 7,912,555; 8,000,805; and 8,036,756. Each tineelement includes a plurality of flexible, pliant, tines. The tines areconfigured to be folded inward against the lead body when fitted intoand constrained by the lumen of an introducer.

Peripheral nerve field stimulation (“PNFS”) involves delivery ofstimulation to a specific peripheral nerve via one or more electrodesimplanted proximate to or in contact with a peripheral nerve, such asdisclosed in U.S. Pat. Publication No. 2009/0281594. PNFS may be used todeliver stimulation to, for example, the vagal nerves, cranial nerves,trigeminal nerves, ulnar nerves, median nerves, radial nerves, tibialnerves, and the common peroneal nerves. When PNFS is delivered to treatpain, one or more electrodes are implanted proximate to or in contactwith a specific peripheral nerve that is responsible for the painsensation.

Tined leads can create problems during removal or explant. Inparticular, the human body recognizes a lead as a foreign body and formsfibrous tissue around the lead. The fibrous tissue strengthens theengagement with the tines. If the anchoring of the tines is strongerthan the lead itself, the lead may break during removal, leavingfragments behind. These fragments can migrate creating pain andincreasing the risk of infection. Additional surgery is often requiredto remove the fragments.

BRIEF SUMMARY

The present disclosure is directed to a therapy delivery element with abraided reinforcement structure having a free end located near theconnector assembly. The present therapy delivery element provides a highdegree of elasticity between the connector assembly and the electrodeassembly, while the high tensile strength of the braided structuredramatically reduces the risk of fracture during removal. During removalfrom the patient, the surgeon grasps the free end of the braidedstructure.

The present disclosure is directed to a therapy delivery elementconfigured for at least partial insertion in a living body. The therapydelivery element includes a conductor assembly with a plurality ofconductors. An electrode assembly is located at a distal end of theconductor assembly. The electrode assembly includes a plurality ofelectrodes that are electrically coupled to the conductors. A connectorassembly is located at a proximal end of the conductor assembly. Theconnector assembly includes a plurality of electrical contacts that areelectrically coupled to the conductors. The braided structure surroundsthe conductor assembly. A distal end of the braided structure isattached to an electrode assembly and a free floating proximal end islocated near a connector assembly. An outer tubing surrounds the braidedstructure. The outer tubing includes a proximal end attached to theconnector assembly and a distal end attached to the braided structurenear the electrode assembly or attached directly to the electrodeassembly. A proximal tension force applied to the connector assemblyacts substantially on the outer tubing and the conductor assembly,providing substantial axial elasticity. A proximal tension force appliedto the free floating proximal end acts substantially on the braidedstructure to provide high tensile strength during removal.

The elongation of the outer tubing section is preferably decoupled fromelongation of the braided section. A tension force applied to the freefloating proximal end is preferably substantially transmitted to theelectrode assembly independent of the outer tubing. A tension forceapplied to the free floating proximal end the therapy delivery elementexhibits a percentage elongation generally corresponding to a percentageelongation of the braided structure. A tension force applied to theconnector assembly exhibits a percentage elongation generallycorresponding to a percentage elongation of the outer tubing and theconductor assembly.

A tension force applied to the free floating end of the braidedstructure provides a percent elongation in a range between about 0.5% toabout 15%. The tension force applied to the free floating end of thebraided structure provides a yield strength in a range between about 8lbs. to about 15 lbs. A tension force applied to the connector assemblyprovides a percent elongation in a range between about 5% to about 30%.The tension force applied to the connector assembly provides a yieldstrength in a range between about 1 lbs. to about 7 lbs. The yieldstrength of the present therapy delivery element when the tension forceis applied to the free floating proximal end of the braided structure isabout 5 times greater than the yield strength when the tension force isapplied to the connector assembly. Consequently, the present therapydelivery element combines a high level of strain relief with sufficienttensile strength to permit removal from the patient with minimal risk offragmentation.

An axial force required to fully stretch the therapy delivery elementbetween the connector assembly and the distal end of the outer tubing isless than about 10% of the yield strength of the therapy deliveryelement between the free floating proximal end and the electrodeassembly.

The braided structure optionally extends substantially to a distal endof the electrode assembly. Inner tubing is optionally bonded to thebraided structure to increase strength and to prevent tissue in-growth.The inner tubing optionally extends substantially to a distal end of theelectrode assembly. A thermoplastic material is optionally melted intoengagement with the braided structure.

At least one fixation structure is optionally attached to the therapydelivery element near the electrode assembly.

The present disclosure is also directed to a neurostimulation systemincluding an implantable pulse generator. A therapy delivery element asdiscussed herein is provided. The electrical contacts on the connectorassembly are configured to electrically couple with the implantablepulse generator.

The present disclosure is also directed to a method of making a therapydelivery element configured for at least partial insertion in a livingbody. The method includes braiding a plurality of fibers to form abraided structure with a lumen. A conductor assembly including aplurality of conductors is located in the lumen of the braidedstructure. An outer tubing is positioned around the braided structureand the conductor assembly. Electrodes on an electrical assembly areelectrically coupled to the conductors at a distal end of the conductorassembly. Electrical connectors on a connector assembly are electricallycoupled to the conductors at a proximal end of the conductor assembly.The braided structure is attached to the electrode assembly, whileleaving a proximal end of the braided structure free floating in theouter tubing. A proximal end of the outer tubing is attached to theconnector assembly. A distal end of the outer tubing is bonded to thebraided structure at or near the electrode assembly. A proximal tensionforce applied to the connector assembly acts substantially on the outertubing and the conductor assembly, and a proximal tension force appliedto the proximal end of the braided structure acts substantially on thebraided structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a therapy delivery system.

FIG. 2A is a schematic illustration of an implantable pulse generatorand a therapy delivery element in accordance with an embodiment of thepresent disclosure.

FIG. 2B is a schematic illustration of a lead extension and a therapydelivery element in accordance with an embodiment of the presentdisclosure.

FIG. 3 is a schematic illustration of a therapy delivery system forspinal cord stimulation in accordance with an embodiment of the presentdisclosure.

FIG. 4 is an alternate illustration of an implantable pulse generatorwith a therapy delivery element in accordance with an embodiment of thepresent disclosure.

FIG. 5 is a schematic illustration of a therapy delivery system fortreating pelvic floor disorders in accordance with an embodiment of thepresent disclosure.

FIG. 6 is a schematic illustration of a therapy delivery system forperipheral nerve stimulation in accordance with an embodiment of thepresent disclosure.

FIG. 7 is a side view of a therapy delivery element with a braidedreinforcement in accordance with an embodiment of the presentdisclosures.

FIG. 8 is a side view a connector assembly of the therapy deliveryelement of FIG. 7.

FIG. 9A is a side sectional view of an electrode assembly for thetherapy delivery element of FIG. 7 in accordance with an embodiment ofthe present disclosure.

FIG. 9B is a side sectional view of an alternate electrode assembly forthe therapy delivery element of FIG. 7 in accordance with an embodimentof the present disclosure.

FIG. 10 is a side sectional view of a bonding location of the outer tubeto the therapy delivery element of FIG. 7 in accordance with anembodiment of the present disclosure.

FIG. 11 is a side sectional view of a proximal end of the braidedreinforcement of the therapy delivery element of FIG. 7 in accordancewith an embodiment of the present disclosures.

FIG. 12A is a side view of an alternate therapy delivery element with abraided reinforcement in accordance with an embodiment of the presentdisclosures.

FIG. 12B is a side sectional view of a proximal end of the braidedreinforcement of the therapy delivery element of FIG. 12A in accordancewith an embodiment of the present disclosures.

FIG. 13 illustrates a portion of method of implanting a therapy deliveryelement in accordance with an embodiment of the present disclosure.

FIG. 14 illustrates a portion of a method of implanting a therapydelivery element in accordance with an embodiment of the presentdisclosure.

FIG. 15 is a flow chart of a method of making a therapy delivery elementin accordance with an embodiment of the present disclosure.

The drawings are not necessarily to scale. Like numbers refer to likeparts or steps throughout the drawings.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The description that follows highlights spinal cord stimulation (SCS)system, the treatment of pelvic floor disorders, and peripheral nervefield stimulation (PNFS). However, it is to be understood that thedisclosure relates to any type of implantable therapy delivery systemwith one or more therapy delivery elements with one or more electrodesor sensors. For example, the present disclosure may be used as part of apacemaker, a defibrillator, a cochlear stimulator, a retinal stimulator,a stimulator configured to produce coordinated limb movement, a corticalstimulator, a deep brain stimulator, microstimulator, or in any otherneural stimulator configured to treat sleep apnea, shoulder sublaxation,headache, etc.

In another embodiment, one or more of the therapy delivery elements maybe a fluid or drug delivery conduit, such as a catheter, including aninner lumen that is placed to deliver a fluid, such as pharmaceuticalagents, insulin, pain relieving agents, gene therapy agents, or the likefrom a fluid delivery device (e.g., a fluid reservoir and/or pump) to arespective target tissue site in a patient.

In yet another embodiment, one or more of the therapy delivery elementsmay be a medical electrical lead including one or more sensingelectrodes to sense physiological parameters (e.g., blood pressure,temperature, cardiac activity, etc.) at a target tissue site within apatient. In the various embodiments contemplated by this disclosure,therapy may include stimulation therapy, sensing or monitoring of one ormore physiological parameters, fluid delivery, and the like, “Therapydelivery element” includes pacing or defibrillation leads, stimulationleads, sensing leads, fluid delivery conduit, and any combinationthereof. “Target tissue site” refers generally to the target site forimplantation of a therapy delivery element, regardless of the type oftherapy.

FIGS. 1 illustrates a generalized therapy delivery system 10 that may beused in stimulation applications. The therapy delivery system 10generally includes an implantable pulse generator 12 (“IPG”) (“IPG”), animplantable therapy delivery element 14, which carries an array ofelectrodes 18 (shown exaggerated for purposes of illustration), and anoptional implantable extension lead 16. Although only one therapydelivery element 14 is shown, typically two or more therapy deliveryelements 14 are used with the therapy delivery system 10.

The therapy delivery element 14 includes lead body 40 having a proximalend 36 and a distal end 44. The lead body 40 typically has a diameterranging between about 0.03 inches to about 0.07 inches and a lengthranging between about 30 cm to about 90 cm for spinal cord stimulationapplications. The lead body 40 may include a suitable electricallyinsulative coating, such as, a polymeric material (e.g., polyurethane orsilicone).

In the illustrated embodiment, proximal end 36 of the therapy deliveryelement 14 is electrically coupled to distal end 38 of the extensionlead 16 via a connector 20, typically associated with the extension lead16. Proximal end 42 of the extension lead 16 is electrically coupled tothe implantable pulse generator 12 via connector 22 associated withhousing 28. Alternatively, the proximal end 36 of the therapy deliveryelement 14 can be electrically coupled directly to the connector 22.

In the illustrated embodiment, the implantable pulse generator 12includes electronic subassembly 24 (shown schematically), which includescontrol and pulse generation circuitry (not shown) for deliveringelectrical stimulation energy to the electrodes 18 of the therapydelivery element 14 in a controlled manner, and a power supply, such asbattery 26.

The implantable pulse generator 12 provides a programmable stimulationsignal (e.g., in the form of electrical pulses or substantiallycontinuous-time signals) that is delivered to target stimulation sitesby electrodes 18. In applications with more than one therapy deliveryelement 14, the implantable pulse generator 12 may provide the same or adifferent signal to the electrodes 18.

Alternatively, the implantable pulse generator 12 can take the form ofan implantable receiver-stimulator in which the power source forpowering the implanted receiver, as well as control circuitry to commandthe receiver-stimulator, are contained in an external controllerinductively coupled to the receiver-stimulator via an electromagneticlink. In another embodiment, the implantable pulse generator 12 can takethe form of an external trial stimulator (ETS), which has similar pulsegeneration circuitry as an IPG, but differs in that it is anon-implantable device that is used on a trial basis after the therapydelivery element 14 has been implanted and prior to implantation of theIPG, to test the responsiveness of the stimulation that is to beprovided.

The housing 28 is composed of a biocompatible material, such as forexample titanium, and forms a hermetically sealed compartment containingthe electronic subassembly 24 and battery 26 protected from the bodytissue and fluids. The connector 22 is disposed in a portion of thehousing 28 that is, at least initially, not sealed. The connector 22carries a plurality of contacts that electrically couple with respectiveterminals at proximal ends of the therapy delivery element 14 orextension lead 16. Electrical conductors extend from the connector 22and connect to the electronic subassembly 24.

FIG. 2A illustrates the therapy delivery element 14 including one ormore electrical contacts 15 at the proximal end 36, and one or moreelectrodes 18 at the distal end 44. The contacts 15 and electrodes 18are electrically coupled via insulated wires running through the therapydelivery element 14. Proximal end 36 of the therapy delivery element 14is electrically and mechanically coupled to implantable pulse generator12 by the connector assembly 22. In the embodiment illustrated in FIGS.2A and 2B, the therapy delivery element 14 forms a medical electricallead.

The connector assembly 22 includes a plurality of discrete contacts 23located in the housing 28 that electrically couple contact rings 15 onthe proximal end of the therapy delivery element 14. The discretecontacts 23 are electrically coupled to circuitry 24 in the implantablepulse generator 12 by conductive members 21. Each contact ring 15 iselectrically coupled to one or more of the electrodes 18 located at thedistal end 44 of the therapy delivery element 14. Consequently, theimplantable pulse generator 12 can be configured to independentlydeliver electrical impulses to each of the electrodes 18.

Alternatively, the therapy delivery element 14 can be coupled to theimplantable pulse generator 12 through one or more lead extensions 16,as illustrated in FIG. 2B. The connector 20 at the distal end 38 of thelead extension 16 preferably includes a plurality of the contacts 23configured in a manner similar to the connector assembly 22.

FIG. 3 illustrates the therapy delivery element 14 used for spinal cordstimulation (SCS) implanted in the epidural space 30 of a patient inclose proximity to the dura, the outer layer that surrounds the spinalcord 32, to deliver the intended therapeutic effects of spinal cordelectrical stimulation. The target stimulation sites may be anywherealong the spinal cord 32, such as the proximate sacral nerves.

Because of the lack of space near the lead exit point 34 where thetherapy delivery element 14 exits the spinal column, the implantablepulse generator 12 is generally implanted in a surgically-made pocketeither in the abdomen or above the buttocks, such as illustrated in FIG.4. The implantable pulse generator 12 may, of course, also be implantedin other locations of the patient's body. Use of the extension lead 16facilitates locating the implantable pulse generator 12 away from thelead exit point 34. In some embodiments, the extension lead 16 serves asa lead adapter if the proximal end 36 of the therapy delivery element 14is not compatible with the connector 22 of the implantable pulsegenerator 12, since different manufacturers use different connectors atthe ends of their stimulation leads and are not always compatible withthe connector 22.

As illustrated in FIG. 4, the therapy delivery system 10 also mayinclude a clinician programmer 46 and a patient programmer 48. Clinicianprogrammer 46 may be a handheld computing device that permits aclinician to program neurostimulation therapy for patient using inputkeys and a display. For example, using clinician programmer 46, theclinician may specify neurostimulation parameters for use in delivery ofneurostimulation therapy. Clinician programmer 46 supports telemetry(e.g., radio frequency telemetry) with the implantable pulse generator12 to download neurostimulation parameters and, optionally, uploadoperational or physiological data stored by implantable pulse generator12. In this manner, the clinician may periodically interrogate theimplantable pulse generator 12 to evaluate efficacy and, if necessary,modify the stimulation parameters.

Similar to clinician programmer 46, patient programmer 48 may be ahandheld computing device. Patient programmer 48 may also include adisplay and input keys to allow patient to interact with, patientprogrammer 48 and the implantable pulse generator 12. The patientprogrammer 48 provides patient with an interface for control ofneurostimulation therapy provided by the implantable pulse generator 12.For example, patient may use patient programmer 48 to start, stop oradjust neurostimulation therapy. In particular, patient programmer 48may permit patient to adjust stimulation parameters such as duration,amplitude, pulse width and pulse rate, within an adjustment rangespecified by the clinician via clinician programmer 46, or select from alibrary of stored stimulation therapy programs.

The implantable pulse generator 12, clinician programmer 46, and patientprogrammer 48 may communicate via cables or a wireless communication.Clinician programmer 46 and patient programmer 48 may, for example,communicate via wireless communication with the implantable pulsegenerator 12 using RF telemetry techniques known in the art. Clinicianprogrammer 46 and patient programmer 48 also may communicate with eachother using any of a variety of local wireless communication techniques,such as RF communication according to the 802.11 or Bluetoothspecification sets, infrared communication, e.g., according to the IrDAstandard, or other standard or proprietary telemetry protocols.

Since the implantable pulse generator 12 is located remotely from targetlocation 50 for therapy, the therapy delivery element 14 and/or theextension lead 16 is typically routed through a pathway 52subcutaneously formed along the torso of the patient to a subcutaneouspocket 54 where the implantable pulse generator 12 is located. As usedhereinafter, “lead” and “lead extension” may be used interchangeably,unless context indicates otherwise.

The therapy delivery elements 14 are typically fixed in place near thelocation selected by the clinician using the present suture anchors 60.The suture anchors 60 can be positioned on the therapy delivery element14 in a wide variety of locations and orientations to accommodateindividual anatomical differences and the preferences of the clinician.The suture anchors 60 may then be affixed to tissue using fasteners,such as for example, one or more sutures, staples, screws, or otherfixation devices. The tissue to which the suture anchors 60 are affixedmay include subcutaneous fascia layer, bone, or some other type oftissue. Securing the suture anchors 60 to tissue in this manner preventsor reduces the chance that the therapy delivery element 14 will becomedislodged or will migrate in an undesired manner.

FIG. 5 illustrates the therapy delivery element 14 used for pelvic floordisorders such as, urinary incontinence, urinary urge/frequency, urinaryretention, pelvic pain, bowel dysfunction (constipation, diarrhea),erectile dysfunction, are bodily functions influenced by the sacralnerves. The organs involved in bladder, bowel, and sexual functionreceive much of their control via the second, third, and fourth sacralnerves, commonly referred to as S2, S3 and S4 respectively. Electricalstimulation of these various nerves has been found to offer some controlover these functions. Several techniques of electrical stimulation maybe used, including stimulation of nerve bundles 72 within the sacrum 70.The sacrum 70, generally speaking, is a large, triangular bone situatedat the lower part of the vertebral column, and at the upper and backpart of the pelvic cavity. The spinal canal 74 runs throughout thegreater part of the sacrum 70. The sacrum is perforated by the posteriorsacral foramina 76 and anterior sacral foramina 78 that the sacralnerves 70 pass through.

Specifically, urinary incontinence is the involuntary control over thebladder that is exhibited in various patients. The therapy deliveryelement 14 is percutaneously implanted through the foramina 76, 78 ofthe sacral segment S3 for purposes of selectively stimulating the S3sacral nerve 72. Stimulation energy is applied through the lead 14 tothe electrodes 18 to test the nerve response. The electrodes 18 aremoved back and forth to locate the most efficacious location, and thelead 14 is then secured by suturing the lead body to subcutaneous tissueposterior to the sacrum 70 and attached to the output of aneurostimulator IPG 12.

FIG. 6 illustrates the therapy delivery element 14 used for deliveringperipheral nerve field stimulation (PNFS) to a patient. Therapy deliveryelement 14 delivers PNFS from the implantable pulse generator 12 to thetissue of patient at target location 50A where patient experiences pain.Clinician programmer 46 and patient programmer 48 may communicate viawireless communication with the implantable pulse generator 12.

Therapy delivery element 14 may be implanted within or between, forexample, intradermal, deep dermal, or subcutaneous tissue of patient atthe location 50A where patient experiences pain. Subcutaneous tissueincludes skin and associated nerves, and muscles and associated nervesor muscle fibers. In the illustrated example, location 50A is a regionof the lower back. In other examples, the therapy delivery element 14may extend from implantable pulse generator 12 to any localized area ordermatome in which patient experiences pain, such as various regions ofthe back, the back of the head, above the eyebrow, and either over theeye or under the eye, and may be used to treat failed back surgerysyndrome (FBBS), cervical pain (e.g., shoulder and neck pain), facialpain, headaches supra-orbital pain, inguinal and pelvic pain, chest andintercostal pain, mixed pain (e.g., nociceptive and neuropathic),visceral pain, neuralgia, peroneal pain, phantom limb pain, andarthritis.

FIGS. 7 and 8 are side views of a therapy delivery element 100 with areinforcing braided structure 102 (see FIG. 9) in accordance with anembodiment of the present disclosure. The therapy delivery element 100includes a connector assembly 104 at proximal end 106 and electrodeassembly 108 at distal end 110. The connector assembly 104 includes aplurality of electrical connectors 122 and the electrode assembly 108includes a plurality of electrodes 124. A conductor assembly 126 (seeFIG. 10) extends through lumen 128 of lead body 130 to electricallycouple the electrical connectors 122 to the electrodes 124. In theillustrated embodiment, the electrode assembly 108 and/or the connectorassembly 104 are discrete molded structures. In an alternate embodiment,the electrodes 124 and/or the electrical connectors 122 are attacheddirectly to the lead body 130.

The therapy delivery element 100 optionally includes fixation structures136, such as symmetrical and asymmetrical protrusions. Various fixationstructures 136 suitable for the present therapy delivery element 100 aredisclosed in commonly assigned U.S. patent application Ser. Nos.13/537,494, pending, entitled Braided Lead with Embedded FixationStructures, filed Jun. 29, 2012 and 13/537,341, pending, entitled LeadPositioning and Finned Fixation System, filed Jun. 29, 2012, which arehereby incorporated by reference.

The braided structure 102 preferably extends along braid section 112from about the distal end 110 to location 114 near the proximal end 106.The location 114 is preferably sufficiently close to the proximal end106 so as to be accessible through the same incision that providesaccess to the implantable pulse generator 12. The proximal section 132between the location 114 and the connector assembly 104 typically has alength of between about 0.5 inches and about 5.0 inches.

In the preferred embodiment, outer tubing 116 extends along outer tubingsection 118 from about the connector assembly 104 to a connectionlocation 120 located along braid section 112. The outer tubing section118 is typically within about 2.5 inches or less from the electrodeassembly 108. In an alternate embodiment, the connection location 120 islocated on the electrode assembly 108 so that the outer tubing 116extends substantially the entire length 115 of the lead body 130.

The braided structure 102 has a lower percent elongation and greaterresistance to axial deformation than the outer tubing 116, whichprovides tensile reinforcement for the therapy delivery element 100between the location 114 and the distal end 110. If the therapy deliveryelement 100 is grasped at the location 114, it will exhibit a tensilestrength corresponding to at least the tensile strength of the braidedstructure 102.

On the other hand, the outer tubing 116 has a higher percent elongationand lower resistance to axial deformation than the braided structure102, which provides greater stretchability for the therapy deliveryelement 100 between the connector assembly 106 and the location 120.Along proximal section 132 near the connector assembly 104 only theouter tubing 116 covers the conductor assembly 126. If the tension force134 is applied to the connector assembly 104, such as may occur when isimplanted in a patient, the therapy delivery element 100 exhibits apercentage elongation generally corresponding to the percentageelongation of the outer tubing 116 and the conductor assembly 126.

Maximizing the length of the outer tubing section 118 maximizes thepercentage elongation of the present therapy delivery element 100. Bydecoupling the outer tubing 116 from the braided structure 102, thepresent therapy delivery element 100 provides both high percentelongation and high tensile reinforcement.

The braided structure 102 preferably has a percent elongation in a rangebetween about 0.5% and about 15.0%, but yield strength in a rangebetween about 8 lbs. and about 15 lbs. The outer tubing 116, on theother hand, preferably has a percent elongation in a range between about5% and about 30%, but a yield strength in a range between about 1 lbs.and about 7 lbs. The axial force required to fully stretch the therapydelivery element 100 between the connector assembly 104 and the location120 is preferably less than about 10% of the yield strength of thebraided structure between the location 114 and the electrode assembly108. The yield strength of the present therapy delivery element 100 whenthe tension force 134 is applied to the free floating proximal end 180of the braided structure 102 (see FIG. 11) is about 2 times to about 15times, and more preferably about 5 times greater than, the yieldstrength when the tension force 134 is applied to the connector assembly104. As a result, the therapy delivery element 100 combines both a highlevel of strain relief with a high tensile strength during extractionfrom the patient.

FIG. 9A is a side sectional view of one embodiment of the electrodeassembly 108 of FIG. 7. Braided structure 102 preferably extends thoughlumen 150 of the electrode assembly 108 to near the distal end 110. Thebraided structure 102 is preferably bonded to the electrode assembly 108along inside surface 156 of the lumen 150. As used herein “bonded” or“bonding” refers to adhesive bonding, solvent bonding, ultrasonicwelding, heat shrinkage, compressive coupling, thermal bonding,mechanical interlocks, and a variety of other techniques. The braidedstructure 102 includes lumen 152 sized to receive the conductor assembly126 (see FIG. 10), allowing the individual conductors 154 to beelectrically coupled to the electrodes 124.

The braided structure 102 includes a plurality of fibers 170. Thebraided structure 102 is preferably an axial braid, although a varietyof other braid patterns or woven structures may be used. As used herein,“braid” or “braided” refers to structures formed by intertwining orweaving three or more strands or fibers of a flexible material. Braidsare preferred because of high tensile strength and good radialflexibility. The braided structure 102 reinforces the lead body 130during ex-plant without losing flexibility. Another advantage of thebraided structure 102 is that braided structure 102 necks down when atensile load is applied. The reduced cross-sectional diameter of thebraided structure 102 during ex-plant facilitates removal and promotesdisengagement from the surrounding tissue.

The fibers 170 are preferably a bio-compatible polymeric material, suchas for example, polyethylene terephthalate (PET), Nylon, polyether etherketone (PEEK), polyproylene, high-performance polyethylenes,bioabsorbale polymers, such as polyglutamic acid (PGA), poly-L-lactide(PLLA), or polycaprolactone (PCL), urethane, silicone, Nitinol,stainless steel, MP35N, titanium, or any combination of these materials.Any number of discrete fibers 170 can be used in the braided structure102, but typically there are about 4 to about 16 fibers. In oneembodiment, some portion of the fibers 170 run clockwise and theremainder run counterclockwise within the braided structure 102.

The fibers 106 are preferably a mono-filament with a diameter in a rangeof about 0.001 inches to about 0.006 inches. Selection of the fibers 170depends on a variety of variables, such as for example, the desireddiameter and/or overall length of the lead body 130. In one embodiment,the braided structure 102 includes about 12 fibers 170 made from PET,each having a diameter of about 0.004 inches.

In another embodiment, some of the fibers 170 are made from a conductivematerial, like copper, platinum, MP35N, or silver, to provide shieldingand grounding for the resulting therapy delivery element. For example,some of the fibers 170 are optionally made from a conductive material toprovide shielding to the lead. In embodiments where the braidedstructure 102 includes metal wires, the tensile strength of the therapydelivery element 100 increases at least about 30% to about 50%.

In the illustrated embodiment, braided structure 102 includes tubing 160that prevents tissue in-growth around fibers 170. The tubing 160 ispreferably bonded or reflowed into the braided structure 102 to increasethe overall strength of the therapy delivery element 100. In theillustrated embodiment, distal end 162A of the tubing 160 is bonded toelectrode assembly 108 at location 164.

The tubing 160 extends in proximal direction 155 to at least thelocation 120 where the outer tubing 116 begins. As a result, the braidedstructure 102 is completely isolated from potential tissue in-growth. Inanother embodiment, the tubing 160 extends the full length of thebraided structure 102 to the location 114.

The tubing 160 increases the yield strength of the braided structure 102by at least 10%. The tubing 160 also serves to protect the conductorassembly 126 from abrasion that might occur when interacting with thefibers 170 of the braided structure 102.

FIG. 9B is a side sectional view of an alternate embodiment in which thetubing 160 extends into the lumen 150 of the electrode assembly 108. Inthe illustrated embodiment, distal end 162B of the tubing 160 is locatedadjacent the distal end 110 of the electrode assembly 108. In theembodiment of FIG. 9B, the outer tubing 116 extends to the electrodeassembly 108. The outer tubing 116 is bonded to the electrode assembly108 at the location 120.

FIG. 10 is a side sectional view of the lead body 130 at the location120 where the outer tubing 116 attaches to the braided structure 102 inaccordance with an embodiment of the present disclosure. In theillustrated embodiment, the outer tubing 116 is bonded to the tubing 160containing the braided structure 102 at the location 120. In anotherembodiment, the outer tubing 116 compressively engages the braidedstructure 102, such as by heat shrinkage, compressive force, and thelike.

In one embodiment, the outer tubing 116 has an inner diameter 172greater than outer diameter 174 of the braided structure 102 (includingthe tubing 160), creating gap 173. The gap 173 minimizes frictionbetween the outer tubing 116 and the inner tubing 160 and the braidedstructure 102. Assuming minimal friction, the gap 173 permits the outertubing 116 to stretch substantially independently from the braidedstructure 102 and the inner tubing 160 during elongation of the therapydelivery element 100. When tensile load 134 is applied to the therapydelivery element 100, the outer tubing 116 necks-down and the gap 173 isreduces or substantially closes.

The tubing 116 and 160 can be constructed from a variety ofbio-compatible polymeric materials, such as for example, polyproylene,high-performance polyethylenes, PLLA, or PCL, urethanes such asTecothane®, silicone, or combination thereof.

Conductor assembly 126 is located in the lumen 152 of the braidedstructure 102 to electrically couple the electrical connectors 122 tothe electrodes 124. The conductor assembly 126 preferably has an outerdiameter 142 that is less than inner diameter 144 of the braidedstructures 102, creating gap 145. Assuming minimal friction between theconductor assembly 126 and the braided structure 102 and tubing 160, thegap 145 permits the conductor assembly 126 to stretch substantiallyindependently of the braided structure 102 and the tubing 160.

The conductor assembly 126 includes one or more conductors 154 (seee.g., FIG. 10) extending through the lumen 128 from the electrodeassembly 108 to the connector assembly 104. Typically there is aone-to-one correlation between the number of electrodes 124, connectors122 and conductors 154. For example, if there are eight electrodes 124and eight connectors 122, the conductor assembly 126 includes eightconductors 154. As used herein, “conductor assembly” refers to one ormore insulated or un-insulated conductive wires or cables arranged in avariety of configurations, including straight, coiled, braided, and thelike, that electrically couple electrodes at one end of a lead body toconnectors at an opposite end. Alternate coil configurations for use inthe conductor assembly 126 are disclosed in commonly assigned U.S.application Ser. No. 13/045,908, now published as U.S. PatentApplication Publication No. 2012/0232625, entitled Implantable Lead withBraided Conductors, filed Mar. 11, 2011; and U.S. application Ser. No.13/220,913, now published as U.S. Patent Application Publication No.2013/0053864, entitled Lead Body with Inner and Outer Co-Axial Coils,filed Aug. 30, 2011, which is hereby incorporated by reference.

The conductors 154 can in include single conductive element, a pluralityconductive wires, or a combination thereof. For example, each conductor154 optionally includes a plurality of un-insulated conductive wirestwisted in a ropelike configuration or cable. Each individual cable isinsulated. The individual wires can be homogenous or a multi-layeredstructure. For example, the core can be silver or copper and the outerlayer can be a nickel-cobalt-chromium-molybdenum alloy, such as forexample, MP35N. According to one embodiment, the cable included seven0.005 inch diameter, silver core MP35N conductors arranged in a 1×7configuration and covered with an ETFE (ethylene tetrafluoroethylene)coating.

The conductor assembly 126 preferably includes lumen 158 configured toreceive a stylet wire 320 that increases the rigidity and columnstrength of the therapy delivery element 100 during implantation (seeFIG. 13). Suitable stylets are disclosed in commonly assigned U.S.patent application Ser. No. 13/222,018, now published as U.S. PatentApplication Publication No. 2013/0053865, entitled Adjustable WireLength Stylet Handle, filed Aug. 31, 2011, and in U.S. Pat. Nos.6,214,016; 6,168,571; 5,238,004; 6,270,496 and 5,957,966, all of whichare hereby incorporated by reference.

FIG. 11 is a side sectional view of unattached or free floating proximalend 180 of the braided structure 102 and the tubing 160 at the location114 in accordance with an embodiment of the present disclosure. Only theouter tubing 116 and the conductor assembly 126 extend from the location114 continue in the proximal direction 155 to the connector assembly104, without the braided structure 102 or the tubing 160.

The present structure decouples the elongation of the outer tubing 116and conductor assembly 126 from the elongation of the braided structure102. In particular, the free floating distal end 180 permits theconductor assembly 126 and outer tubing 116 to elongate independentlyfrom the braided structure 102.

As discussed herein, the outer tubing section 118 exhibits asignificantly greater percent elongation than the braided section 112.If a tension force 134 is applied to the connector assembly 104, thetherapy delivery element 100 exhibits a percentage elongation generallycorresponding to a percentage elongation of the outer tubing 116 and theconductor assembly 126. The tension force 134 on the connector assembly104 is carried primarily by the outer tubing 116 and the conductorassembly 126. The present therapy delivery element 100 provides apercent elongation in a range of between about 10% to about 30%.

On the other hand, if the tension force 134 is applied to the freefloating proximal end 180, the therapy delivery element 100 exhibits apercentage elongation generally corresponding to a percentage elongationof the braided structure 102 and the tubing 160. The tension force 134applied to the free floating proximal end 180 is substantiallytransmitted to the electrode assembly 108 independent of the outertubing 116, greatly reducing the risk of breakage during removal fromthe patient.

During removal of the therapy delivery element 100 from the living body,the surgeon makes an incision near the implantable pulse generator 28 toexpose the therapy delivery element 100. Since the braided section 112extends to a location 114 near the connector assembly 104, the braidedstructure 102 is visible to the surgeon. The surgeon grasps the therapydelivery element 100 along the braided section 112 and pulls. Most ofthe tension force 134 is carried by the braided structure 102 and thetubing 160. The higher tensile properties of the braided structure 102are transmitted to the electrode assembly 108, greatly reducing the riskof breaks during removal from the patient.

The braided structure 102 reinforces the therapy delivery element 100during removal, without compromising compliance. By not running thebraided structure 102 the entire length of the therapy delivery element100, however, the therapy delivery element 100 exhibits a percentelongation far greater than conventional braided leads.

FIGS. 12A and 12B illustrate an alternate therapy delivery element 200without the outer tubing 116 of FIG. 7, in accordance with an embodimentof the present disclosure. The therapy delivery element 200 includebraided structure 202 surrounded by tubing 204, as illustrated in FIG.9A. The tubing 204 extends from connector assembly 206 to electrodeassembly 208 to protect the conductor assembly 218 and the preventtissue in-growth. The braided structure 202, however, extends from theconnection location 214 to near the distal end 212.

As best illustrated in FIG. 12B, the braided structure 202 terminates atthe location 214, but the tubing 204 continues to the connector assembly206, protecting the conductor assembly 218. The braided structure 202provides tensile reinforcement for the therapy delivery element 200between the connection location 214 and the distal end 212. Alongproximal section 220 near the connector assembly 206, however, only thetubing 204 covers the conductor assembly 218.

The outer tubing section 220 exhibits a significantly greater percentelongation than the braided section 210. If a tension force 222 isapplied to the connector assembly 206, the therapy delivery element 200exhibits a percentage elongation generally corresponding to a percentageelongation of the outer tubing section 220 and the conductor assembly218. The tension force 222 on the connector assembly 206 is carriedprimarily by the outer tubing section 220 and the conductor assembly218.

On the other hand, if the tension force 222 is applied at the location214, the therapy delivery element 200 exhibits a percentage elongationgenerally corresponding to a percentage elongation of the braidedstructure 202 and the tubing 204. The tension force 222 applied at thelocation 214 is substantially transmitted to the electrode assembly 208independent of the more elastic outer tubing section 220, greatlyreducing the risk of breakage during removal from the patient.

To remove the therapy delivery element 200 from a living body, thesurgeon grasps the therapy delivery element 200 along the braidedsection 210 and pulls. The braided structure 202 reinforces the therapydelivery element 200 during removal, without compromising compliance. Bynot running the braided structure 202 the entire length of the therapydelivery element 200, however, the therapy delivery element 200 exhibitsa percent elongation far greater than conventional braided leads.

FIG. 13 illustrates one embodiment of a therapy delivery element 300 insacral nerve in accordance with an embodiment of the present disclosure.The therapy delivery element 300 and the fixation structures 302 (seeFIG. 14) are disposed within introducer 304. The introducer 304 isadvanced percutaneously at a selected angle until the introducer distalend 306 is disposed at the selected foramen 308. The therapy deliveryelement 300 may be inserted near any of the sacral nerves including theS1, S2, S3, or S4, sacral nerves accessed via the corresponding foramendepending on the necessary or desired physiologic response.

In one embodiment, the advancement of the introducer 304 can beaccomplished separately over a guide wire previously percutaneouslyadvanced from the skin incision into the foramen to establish the angleof advancement. In yet another embodiment, a multipart introducer can beemployed having an inner introducer element that may be first advancedto the site by itself or over a previously introduced guide wire, and anouter introducer can be introduced over the inner element to dilate thetissue, whereupon the inner element is removed. Any percutaneousintroduction tools and techniques may be employed that ultimately resultin the introducer 304 at the location of FIG. 13. The therapy deliveryelement 300 is optionally stiffened by stylet 320 disposed in the lumen.

As illustrated in FIG. 14, the introducer 304 is retracted proximally indirection 310 after electrical testing of the therapy delivery element300. The fixation structures 302 are released from the introducer 304and engage with surrounding subcutaneous tissue 312. The fixationstructures 302 preferably engage with the muscle tissue located alongposterior surface 322 of the sacrum 324. In one embodiment the fixationstructures 302 can be seen under fluoroscopy to allow the physician toverify that the fixation structures 302 are deployed. As shown in FIG.5, the proximal portion 314 of the lead body 316 is bent and implantedthrough a subcutaneously tunneled path to the implantable pulsegenerator 12.

FIG. 15 is a flow chart directed to a method of making a therapydelivery element configured for at least partial insertion in a livingbody according to an embodiment of the present disclosure. The methodincludes braiding a plurality of fibers to form a braided structure witha lumen (350). A conductor assembly including a plurality of conductorsis located in the lumen of the braided structure (352). An outer tubingis positioned around the braided structure and the conductor assembly(354). Electrodes on an electrical assembly are electrically coupled tothe conductors at a distal end of the conductor assembly (356).Electrical connectors on a connector assembly are electrically coupledto the conductors at a proximal end of the conductor assembly (358). Thebraided structure is attached to the electrode assembly, while leaving aproximal end of the braided structure free-floating in the outer tubing(360). A proximal end of the outer tubing is attached to the connectorassembly (362). A distal end of the outer tubing is bonded to thebraided structure near the electrode assembly (364). A proximal tensionforce applied to the connector assembly acts substantially on the outertubing and the conductor assembly (366). A proximal tension forceapplied to the proximal end of the braided structure acts substantiallyon the braided structure (368).

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range is encompassed within this disclosure. The upper and lowerlimits of these smaller ranges which may independently be included inthe smaller ranges is also encompassed within the disclosure, subject toany specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either bothof those included limits are also included in the disclosure.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosure belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the various methods and materials arenow described. All patents and publications mentioned herein, includingthose cited in the Background of the application, are herebyincorporated by reference to disclose and described the methods and/ormaterials in connection with which the publications are cited.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present disclosure isnot entitled to antedate such publication by virtue of prior invention.Further, the dates of publication provided may be different from theactual publication dates which may need to be independently confirmed.

Other embodiments are possible. Although the description above containsmuch specificity, these should not be construed as limiting the scope ofthe disclosure, but as merely providing illustrations of some of thepresently preferred embodiments. It is also contemplated that variouscombinations or sub-combinations of the specific features and aspects ofthe embodiments may be made and still fall within the scope of thisdisclosure. It should be understood that various features and aspects ofthe disclosed embodiments can be combined with or substituted for oneanother in order to form varying modes disclosed. Thus, it is intendedthat the scope of at least some of the present disclosure should not belimited by the particular disclosed embodiments described above.

Thus the scope of this disclosure should be determined by the appendedclaims and their legal equivalents. Therefore, it will be appreciatedthat the scope of the present disclosure fully encompasses otherembodiments which may become obvious to those skilled in the art, andthat the scope of the present disclosure is accordingly to be limited bynothing other than the appended claims, in which reference to an elementin the singular is not intended to mean “one and only one” unlessexplicitly so stated, but rather “one or more.” All structural,chemical, and functional equivalents to the elements of theabove-described preferred embodiment that are known to those of ordinaryskill in the art are expressly incorporated herein by reference and areintended to be encompassed by the present claims. Moreover, it is notnecessary for a device or method to address each and every problemsought to be solved by the present disclosure, for it to be encompassedby the present claims. Furthermore, no element, component, or methodstep in the present disclosure is intended to be dedicated to the publicregardless of whether the element, component, or method step isexplicitly recited in the claims.

1. A method of making a therapy delivery element configured for at leastpartial insertion in a living body, the method comprising: braiding aplurality of fibers to form a braided structure with a lumen; locating aconductor assembly including a plurality of conductors in the lumen ofthe braided structure; positioning an outer tubing around the braidedstructure and the conductor assembly; electrically coupling electrodeson an electrode assembly to the conductors at a distal end of theconductor assembly; electrically coupling electrical connectors on aconnector assembly to the conductors at a proximal end of the conductorassembly; attaching the braided structure to the electrode assembly,while leaving a proximal end of the braided structure free floating inthe outer tubing, wherein the free floating proximal end of the braidedstructure is unattached to, but disposed within, the outer tubing;attaching a proximal end of the outer tubing to the connector assembly;and bonding a distal end of the outer tubing to the braided structurenear the electrode assembly, wherein: with a first proximal tensionforce applied to the connector assembly, a first elongation of thetherapy delivery element substantially corresponds to a first elongationof the outer tubing and the conductor assembly with a second proximaltension force applied to the free floating proximal end of the braidedstructure, a second elongation of the therapy delivery elementsubstantially corresponds to a second elongation of the braidedstructure; and with the first proximal tension force equal to the secondproximal tension force, the first elongation of the therapy deliveryelement with the first proximal tension force applied to the connectorassembly is greater than the second elongation of the therapy deliveryelement with the second proximal tension force applied to the freefloating proximal end of the braided structure.
 2. The method of claim1, comprising: applying a tension force to the proximal end of thebraided structure; and transmitting the tension force substantially tothe electrode assembly independent of the outer tubing.
 3. The method ofclaim 1, comprising applying the first proximal tension force to theconnector assembly such that the therapy delivery element exhibits apercentage elongation generally corresponding to a percentage elongationof the outer tubing and the conductor assembly.
 4. The method of claim1, comprising: applying a first axial force to axially deform of thetherapy delivery element between the connector assembly and the distalend of the outer tubing; and applying a second axial force to axiallydeform the therapy delivery element between the free floating proximalend and the electrode assembly, wherein the first axial force is 10% orless than the second axial force.
 5. The method of claim 1, comprisingbonding an inner tubing to the braided structure.
 6. The method of claim1, comprising bonding an inner tubing to the braided structure, whereinthe outer tubing surrounds the inner tubing, an inner diameter of theouter tubing being greater than an outer diameter of the inner tubing toform a gap between the inner tubing and the outer tubing.
 7. The methodof claim 1, wherein bonding the distal end of the outer tubing to thebraided structure includes bonding the outer tubing to the braidedstructure such that the outer tubing is configured to be elongatableindependently of the braided structure.
 8. The method of claim 1,comprising melting a thermoplastic material into engagement with thebraided structure.
 9. A method of making a therapy delivery elementconfigured for at least partial insertion in a living body, the methodcomprising: locating a conductor assembly including at least oneconductor within a lumen of a braided structure; positioning an outertubing around the braided structure; electrically coupling at least oneelectrode of an electrode assembly to the at least one conductor at adistal end of the conductor assembly; electrically coupling at least oneelectrical connector of a connector assembly to the at least oneconductor at a proximal end of the conductor assembly; attaching thebraided structure to the electrode assembly, the braided structureincluding a free floating proximal end, wherein the free floatingproximal end of the braided structure is unattached to, but disposedwithin, the outer tubing; and attaching a proximal end of the outertubing to the connector assembly, wherein: with a first proximal tensionforce applied to the connector assembly, a first elongation of thetherapy delivery element substantially corresponds to a first elongationof the outer tubing and the conductor assembly; with a second proximaltension force applied to the free floating proximal end of the braidedstructure, a second elongation of the therapy delivery elementsubstantially corresponds to a second elongation of the braidedstructure; and with the first proximal tension force equal to the secondproximal tension force, the first elongation of the therapy deliveryelement with the first proximal tension force applied to the connectorassembly is greater than the second elongation of the therapy deliveryelement with the second proximal tension force applied to the freefloating proximal end of the braided structure.
 10. The method of claim9, comprising bonding a distal end of the outer tubing to the braidedstructure proximate the electrode assembly.
 11. The method of claim 9,comprising braiding a plurality of fibers together to form the braidedstructure.
 12. The method of claim 9, comprising bonding an inner tubingto the braided structure.
 13. The method of claim 9, comprising bondingan inner tubing to the braided structure, wherein the outer tubingsurrounds the inner tubing, an inner diameter of the outer tubing beinggreater than an outer diameter of the inner tubing to form a gap betweenthe inner tubing and the outer tubing.
 14. The method of claim 9,wherein bonding the distal end of the outer tubing to the braidedstructure includes bonding the outer tubing to the braided structuresuch that the outer tubing is configured to be elongatable independentlyof the braided structure.
 15. The method of claim 9, comprising meltinga thermoplastic material into engagement with the braided structure. 16.A method of making a therapy delivery element configured for at leastpartial insertion in a living body, the method comprising: locating aconductor assembly including a conductor within a lumen of a braidedstructure; positioning an outer tubing around the braided structure;electrically coupling an electrode of an electrode assembly to theconductor at a distal end of the conductor assembly; electricallycoupling an electrical connector of a connector assembly to theconductor at a proximal end of the conductor assembly; attaching thebraided structure to the electrode assembly, the braided structureincluding a free floating proximal end, wherein the free floatingproximal end of the braided structure is unattached to, but disposedwithin, the outer tubing; and attaching a proximal end of the outertubing to the connector assembly, wherein: with a first proximal tensionforce applied to the connector assembly, a first elongation of thetherapy delivery element substantially corresponds to a first elongationof the outer tubing and the conductor assembly; and with a secondproximal tension force applied to the free floating proximal end of thebraided structure, a second elongation of the therapy delivery elementsubstantially corresponds to a second elongation of the braidedstructure.
 17. The method of claim 16, wherein an axial force requiredto fully stretch the therapy delivery element between the connectorassembly and the distal end of the outer tubing is less than about 10%of the yield strength between the free floating proximal end of thebraided structure and the electrode assembly.
 18. The method of claim16, wherein, with the first proximal tension force equal to the secondproximal tension force, a yield strength of the therapy delivery elementwith the second proximal tension force applied to the free floatingproximal end of the braided structure is at least 5 times greater thanthe yield strength of the therapy delivery element with the firstproximal tension force applied to the connector assembly.
 19. The methodof claim 16, comprising bonding an inner tubing to the braidedstructure, wherein the outer tubing surrounds the inner tubing, an innerdiameter of the outer tubing being greater than an outer diameter of theinner tubing to form a gap between the inner tubing and the outertubing.
 20. The method of claim 16, wherein bonding the distal end ofthe outer tubing to the braided structure includes bonding the outertubing to the braided structure such that the outer tubing is configuredto be elongatable independently of the braided structure.